function xuehua(dom,time){
			let box_x = $(dom).width()
			let box_y = $(dom).height()
			var x = 14;
			var y = 10;
			var xue_upt = 4000;
			var xue_dowt =2000;
			var xue_size = 0;
			var xue_le = 0;
			var xue_time = 0;
			var xue_uple = 300;
			var xue_dowle = -300;
			var xue_ovle = 0;
			var xue_upop = 1.1;
			var xue_dowop = 0.5;
			var xue_op = 0;
			setInterval(function (){
				xue_size = parseInt(Math.random() * (x - y + 1) + y)
				xue_le = parseInt(Math.random() * (box_x - 0 + 1) + 0)
				xue_time = Math.random() * (xue_upt - xue_dowt + 1) + xue_dowt
				xue_ovle = xue_le+parseInt(Math.random() * (xue_uple - xue_dowle + 1) + xue_dowle)
				xue_op = (Math.random()* (xue_upop - xue_dowop) + xue_dowop).toFixed(2)
				var span = `
					<span style='width:${xue_size}px;height:${xue_size}px;border-radius:${xue_size}px;left:${xue_le}px;top:0;opacity:${xue_op};'></span>
				`
				$(dom).append($(span))
				for(let i = 0;i<$('span').length;i++){
					if(i==$('span').length-1){
						$('span').eq(i).animate({
							'top':box_y+'px',
							'left':xue_ovle+'px'
						},xue_time,function(){
							$(this).remove()
						})
					}
					
				}
			},time)
			
			
		}